Pressure is on the GOP to deliver on one of its top campaign promises following Democratic wins in state and local elections this week. Passing a major piece of legislation — especially following the failure to repeal and replace Obamacare this summer — could win over moderate voters becoming disenchanted with the party.

The Senate plan, like the House version, features billions in cuts to individuals and businesses. This includes slashing the corporate rate from 35 percent to 20 in a move heavily favored by President Donald Trump and the business community. The corporate rate cut would be delayed one-year to contain costs, though, in a break from Trump's call for an immediate change and the House plan.

It nearly doubles the standard deduction to $12,000 for individuals, $24,000 for married couples and $18,000 for single parents.

It ends deductions for state and local taxes, which doesn't have support from moderate Republicans and lawmakers from higher-taxed states. The House version keeps the deduction only for property taxes up to $10,000.

It keeps the number of tax brackets at seven (10 percent, 12 percent, 22.5 percent, 25 percent, 32.5 percent, 35 percent, 38.5 percent). It also expands the zero tax bracket and decreases the rate for high-income earners 1.3 percent. The House plan has four brackets.

Breaking from the House plan, it preserves the mortgage interest deduction. This means the deduction for mortgage interest would be capped at $1 million, while the House plan caps reduces the limit to $500,000.

Instead of eliminating the estate tax, known by critics as the "death tax," it doubles the current exemption to limit the amount of people paying it. The House plan cuts it completely.

"The conversation, the negotiation will continue until we arrive on consensus," Republican Texas Sen. Ted Cruz said of the initial plan he saw in the conference. "This is an ongoing discussion."

Trump says the upper chamber's measure will go over with Democratic lawmakers better than the House's.

"You're going to like it a whole lot more," Trump told Democratic senators at a meeting he called into, according to The Wall Street Journal.

The House Ways and Means Committee passed its revised bill Thursday afternoon, setting it up for a full House vote expected next week. Revisions restored the Child Adoption Tax Credit, which is already part of the Senate bill, and increased the rate reduction for qualified "pass-through" businesses that send earnings to their owners to be taxed as individual income.

The bipartisan Congressional Budget Office gave the House bill a black eye by saying its first draft would add $1.7 trillion in debt over the next decade. The bill is allowed to add $1.5 trillion to the deficit over the decade, though budget hawks from both parties see any major increase in debt as a non-starter.

Any bill that comes out of the House would have to be reconciled with the Senate's version, then voted on again. Trump said he wants a tax reform package — one he heralds as the largest in history — on his desk by Christmas. That's a tight timetable, but one that is important to meet if the Senate wants to avoid losing protection on filibusters.

A confident House Speaker Paul Ryan said late Thursday morning, "we're going to get this across the finish line."